The present invention relates to electrophotographic image forming equipment and, more particularly, to a control device for electrophotographic image forming equipment capable of reducing ozone ascribable to the image forming process of the equipment and detecting errors of the equipment caused by the ozone.
A copier, facsimile transceiver, laser beam printer or similar electrophotographic image forming equipment is extensively used today. An electrophotographic procedure includes a step of uniformly charging an image carrier, a step of transferring a developed image or toner image from the image carrier to a paper sheet, a step of separating the paper sheet with the toner image from the image carrier, and a step of dissipating the charge remaining on the image carrier after the image transfer. These steps are implemented with at least chargers for corona discharge and, therefore, generate ozone which gives out an offensive smell. Regarding an electrophotographic copier of the type using a liquid developer, the smell particular to the ozone has not been a problem since such a type of copier does not emit a noticeable amount of ozone to the outside, i.e., mists of liquid developer produced in the copier contact and thereby decompose ozone.
However, modern copiers with high-speed and large format copying capabilities are implemented with chargers having greater power to be stably operable. The increase in the power of chargers directly translates into the increase in the concentration of ozone to be produced in the copier, influencing even the copier of the type using a liquid developer. Typically, the liquid developer for use with a copier comprises a toner-dispersed solvent or carrier liquid which is based on isoparaffine. The mists of the solvent contact the ozone to lower the concentration of the latter. The problem with an isoparaffin-based solvent is that heat oxidizes it and thereby causes it to give out an offensive smell. In a copier, for example, the solvent vaporizes during the fixing step due to heat generated by a heater which is incorporated in a fixing roller, resulting in an foul smell. Hence, mists of the solvent evaporated at the fixing step do not mix with the ozone. Customarily, therefore, it has been expected that the ozone automatically contacts the mists generated around a photoconductive drum, or image carrier, which are derived partly from the rotation of a cleaning roller, partly from the rotation of the developing roller, and partly from the separation of a paper sheet from the drum.
However, simply expecting the automatic contact of the ozone with the mists generated around the drum is too negative and inefficient to achieve sufficient reduction in the concentration of ozone.